Table 2.
All Thyroid | Papillary Carcinoma | |||
---|---|---|---|---|
| ||||
Cases | HR (95% CI)a | Cases | HR (95% CI)a | |
Age at menarche | ||||
<12 years | 33 | 1.00 (reference) | 25 | 1.00 (reference) |
12–13 years | 70 | 0.84 (0.55–1.27) | 57 | 0.91 (0.57–1.46) |
≥14 years | 24 | 0.62 (0.36–1.05) | 17 | 0.60 (0.32–1.11) |
P-trendb | 0.08 | 0.11 | ||
Type of menopause | ||||
Natural | 74 | 1.00 (reference) | 58 | 1.00 (reference) |
Hysterectomy, both ovaries removed | 17 | 1.21 (0.71–2.06) | 16 | 1.47 (0.84–2.56) |
Hysterectomy, still has ≥1 ovaries/unknown | 31 | 1.22 (0.80–1.86) | 22 | 1.13 (0.69–1.85) |
Age at natural menopausec,e | ||||
<50 years | 21 | 1.00 (reference) | 14 | 1.00 (reference) |
50–54 years | 34 | 1.08 (0.62–1.86) | 29 | 1.38 (0.73–2.61) |
≥55 years | 19 | 2.24 (1.20–4.18) | 15 | 2.65 (1.28–5.51) |
P-trendb | 0.02 | 0.01 | ||
Number of reproductive yearsd,e | ||||
<35 years | 20 | 1.00 (reference) | 14 | 1.00 (reference) |
35–40 years | 27 | 0.83 (0.46–1.48) | 22 | 0.96 (0.49–1.88) |
>40 years | 27 | 1.71 (0.96–3.07) | 22 | 1.97 (1.00–3.87) |
P-trendb | 0.05 | 0.03 | ||
Lifetime number of ovulatory cyclese | ||||
<415 cycles | 22 | 1.00 (reference) | 16 | 1.00 (reference) |
415–489 cycles | 28 | 1.27 (0.73–2.23) | 25 | 1.54 (0.82–2.90) |
≥ 490 cycles | 24 | 2.40 (1.33–4.30) | 17 | 2.27 (1.13–4.53) |
P-trendb | 0.01 | 0.02 | ||
Number of live births | ||||
Nulliparous | 13 | 1.40 (0.69–2.85) | 9 | 1.06 (0.44–2.60) |
1 or 2 | 34 | 1.00 (reference) | 26 | 1.00 (reference) |
3 | 27 | 0.98 (0.59–1.63) | 22 | 1.06 (0.60–1.87) |
4 | 19 | 1.04 (0.59–1.83) | 13 | 0.94 (0.48–1.85) |
≥5 | 34 | 1.72 (1.05–2.82) | 29 | 1.98 (1.14–3.43) |
P-trendb,f | 0.04 | 0.03 | ||
Age at birth of first child among parous womend | ||||
<20 years | 26 | 1.00 (reference) | 19 | 1.00 (reference) |
20–24 years | 60 | 0.83 (0.51–1.34) | 47 | 0.89 (0.51–1.56) |
≥25 | 27 | 0.60 (0.34–1.08) | 23 | 0.68 (0.35–1.33) |
P-trendb | 0.09 | 0.26 | ||
Tried becoming pregnant without success | ||||
Never | 107 | 1.00 (reference) | 84 | 1.00 (reference) |
Ever | 20 | 1.10 (0.68–1.77) | 15 | 1.05 (0.60–1.82) |
Oral contraceptive use | ||||
Never | 51 | 1.00 (reference) | 42 | 1.00 (reference) |
Ever | 76 | 1.15 (0.79–1.68) | 57 | 1.05 (0.69–1.60) |
Hormone therapy status | ||||
Never | 41 | 1.00 (reference) | 33 | 1.00 (reference) |
Former | 18 | 0.86 (0.50–1.50) | 14 | 0.83 (0.45–1.56) |
Current | 68 | 0.99 (0.67–1.49) | 52 | 0.94 (0.60–1.48) |
Tubal Ligation | ||||
Never | 89 | 1.00 (reference) | 70 | 1.00 (reference) |
Ever | 38 | 1.46 (0.99–2.16) | 29 | 1.42 (0.91–2.23) |
Adjusted for education (less than high school graduate, high school graduate, college graduate), race (non-Hispanic white, non-Hispanic black, Hispanic, Asian/Pacific Islander/American Indian), marital status (married or living as married, widowed, divorced/separated, never married), family history of thyroid cancer, baseline BMI status (<25 kg/m2, 25–29 kg/m2, ≥30 kg/m2), and smoking status (never smoked, former smoker, current smoker) with attained age as the underlying time variable
P-trend calculated by modeling the categorical variable as continuous
Age at natural menopause defined as when the participant reported having their last period
Number of years between age at menarche and age at natural menopause
Restricted to women with natural menopause
Excludes participants reporting never pregnant or no live births